Apple requires MDM services to obtain an Apple Push Notification Service (APNs) certificate to manage iOS devices. The APNs certificate must be renewed yearly. If the certificate expires, iOS devices continue to operate normally, but they no longer trust APNs commands. All of your iOS devices are effectively unmanaged.
| If a certificate expires, it cannot be renewed. Instead, you must create a new certificate and your users must re-enroll all of their managed iOS devices. |
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